Regulating mechanism



May l5, 1945 M; LEvlNE 2,376,144

REGULATING MECHANI SM Filed Jan. 1'?, 1944 2 Sheets-Sheet 2 Inventor: Maw-tin Levine,

bg WM5/JMW His Abto'heg.

Patented May. 15, 1945 REGULATING MEcnANisM Martin Levine, Schenectady, N. Y., assignor to General ElectricA Company, a corporation of New York Application January 17, 1944, serial No. 513,532

lol. zoo-81.5)

3 Claims.

The present invention relates to regulating mechanisms or governing mechanisms and particularly to such mechanisms which embody a follow-up mechanism to prevent hunting or unstable operation.

The invention is well adapted for use on aircraft as a regulator or governor for a control valve and it is this application of my invention which I have elected specifically to illustrate and describe. It is to be understood, however, that this vis only by way of example and that the invention may be used wherever found applicable.

The object of my invention isto provide an improved construction and arrangement of regulating mechanism or governing mechanism, and for a consideration of what I believe to be novel and my invention, attention is directed to the following specification and to the claims appended thereto.

In the drawings, Fig. 1 is a' view, partly in section, of a regulator or governor embodying 'nv invention; Fig. 2 is a detail sectional view taken on line 2-2,v Fig. 1; Fig. 3 is a detail sectional view taken on line 3-3, Fig. 1; Fig. 4 is a perspective view of a part of the mechanism with parts broken away and with the perspective as to certain elements distorted somewhat to better show theI construction; and Fig. is a diagrammatic view showing the application of thev governor or regulator to the control valve of a turbo-supercharger for supercharging an aircraft engine. In Fig. 5 only suflicient mechanism is shown to illustrate an application of my invention. A regulator or governor embodying my invention may be used in connection with a regulating system s'uchas that shown inthe application of Hoffman & Crever, Serial No. 481,444, led April 1, 1943, and assigned to the same assignee as the present application, or it may lbe used in connection With a. system such as that shown in the application of Ridgley, lTruesdell and Anderson, Serial No. 518,568 led of even date herewith and assigned to the same assignee as the present application. The mechanism is enclosed in a casing which for convenience of description may be considered as comprising a top wall I, a bottom wall 2, end walls 3 and 4, and sidewalls 5 and 6. Side wall 6 is attachedA to the top, bottom and end walls by screws 1, thus forming the cover of the box.

Fixed to side wall 5 in vertically spaced relation to each other are two posts 8 and 9 to the ends of which is fastened a strap I0 bymeans of screws I. Strap I0 is shown partly broken away in Fig. 4 an-d the upper post 9 has been omitted in order better to illustrate the structure. Adjustably mounted in strap I0 is a pivot pin I2 having two bearing surfaces, o ne of which is larger' in diameter than the other, as shown particularly in Fig. 4, 'and carried by wall 5 directlyopposite pivot pin I2 is a similar pivot pin I2, Pivot pin I2 is fixed in position by a lock nut |21. Pivotally mounted on the twopivot pins on the bearing surfaces of larger diameter is an arm I3 which for the most part is L-shaped in section, as shown particularly in Figs. 3 and 4. A t its right-hand end it is provided with an enlarged portion |4 around which is wrapped a piece of suitable spring metal I5 which terminates at one end in a spring finger I6 located in spaced relation tothe inner surface portion I4. Located between spring finger I6 and portion I4 is a head l1 on the end of a shaft I8, which shaft at its other end is fixed to one end of a fiat crank arm I9 located in a transverse groove in the end of a head 20. It is held in the groove in head 20 by a disk 2| which is xed to the head by screws 2 l"4 and which carries arms 22 and 23 having angularly extending ends adapted to engage spring straps 24 and 25 to bring such straps into engagement with operating buttons 26 of limit switches 21 and 28. The disk 2| is cut away between arms 22 and 23 to provide a slot throughy which shaft I8 extends. Crank arm I9 has an inturned end 29 provided with a tapped opening in which is located an adjusting screw 30, which screw is carried on the end of a pin 3| passing through and pivotally mounted in an opening in head 20 (Fig. 2). By turning screw 30, the effective length of crank arm I9, i. e., the Vposition of ball |'I with respect to head 2U, may be.adjusted after which it can be locked in adjusted position by the set nut 32. Head 20 is carried by a shaft 33 pivoted in a bushing mounted in an opening in end wall 4. On the screw threaded outer end of shaft 33 is a nut which holds the shaft in .place and which is provided with a toothed collar 34 with which engages a toothed portion on the inner end of an actuating arm 3 5, the parts being held in engagementby a nut 36. By loosening nut 36, the direction in which arm 35 extends relatively to crank arm I9 may be adjusted after which it may be locked in adjusted position by-again tightening the nut 36. With the above described arrangement, it will be seen that when arm 35 is moved, head 20 is turned to eil'ect turning movement of lever I3 on pivot pin 2.

At its left-hand end, lever I3 is in the form of a rectangular yoke 31 to the upper and lower arms of which are fixed spring contact strips 38 and 39. The free ends of contact strips 38 and 39 terminate in parallel portions provided with contact buttons; also, between such ends is located a head 40, oblong in cross section, and carried on the end of a shaft 4| pivotally mounted invan opening in lever I3 and held frictionally' from turning by a spring Washer and nut lla. By turning shaft 4I, head 40 may 4be turned to adjust the distance apart at which stand the contact buttons on spring arms38 and 39. The

head 40 is provided with a squared portion 42 to receive a tool for turning the head when it is to be adjusted. Lever I3 is preferably made of suitable insulating material; or if not made of insulating material, then the contact strips 3B and 39 are suitably insulated with respect to it. Each contact strip embodies an eye 43 to which may be connected a lead wire for the electrical circuit in which the contacts are connected.

Mounted on the smaller diameter portions of the pivot pins is a contact arm 50 comprising a central rectangular portion and rightand lefthand end portions 5| and 52. The contact lever may be made of suitable conducting ymaterial so that it may be connected directly into an electrical circuit. The right-hand portion 5| comprises a contact strip 53 which stands between the contact buttons on spring arms 38 and 39 and is adapted to make contact with them. The left-hand portion 52 of the lever comprises a yoke, extending across and xed in the free ends of which is a pin, 54 which engages a fiat surface on the free end of a lever arm 55 pivoted on ears projecting inwardly from end wall 3, as is indicated at 56. Lever arm 55 isv provided with a downwardly projecting stop ringer 51 which is adapted to engage end wall 3 to limit downward movement of the leverarm on its pivot. Lever arm 55 is provided with a pair of spaced ears 58 in which is rotatably mounted a threaded rod 59, it being provided with a knurled head 59a by means of which it may be turned. On

vto top wall I is an axially extending opening 55 normally closed by a cover cap 66. In use, bellows 6|4 is evacuated and the evacuation may be carried out through the opening 5|, the opening then being sealed by cap 66.

Pivotally connected to lever arm 55 in opposed relation to bellows 6| is a second bellows 61, the upper or movable end of which is provided with spaced ears through which the bellows is pivotally connected to the lever by a suitable pin, as is indicated at 68. The lower lor fixed end of bellows 61 is sealed to the upper end of a sleeve 69 fastened in an opening in bottom casing wall 2 'by means of a cap 10 fixed in place by studs 1|. Connected with cap 10 is a pipe line 12 through which a control pressure may be conveyed to the interior of bellows 61. Inside bellows 61 is a coiled tension spring 13, the upper end of which is connected to the top plate of the bellows, as is indicated at 14, and the lower end of which threads onto a head o n the upper end of a post 16 which projects out through a packn ing gland 11 in cap 10 and has on its threaded outer end a nut 18 provided with a pair of spaced annular shoulders 19. Engaged with the annular groove formed by shoulders 19 is a yoke on the end of an arm 80 fixed on one end of a shaft 8| pivoted in a pair of ears 82 depending from cap 10. Also. xed on shaft 8| is an operating arm 83 to the free end of which may :be connected a control rod 84 which extends to a suitable control lever (not shown). Movement of control rod 84 turns shaft 8| to lower and raise rod 16, the rod sliding through the packing gland be vadjusted by turning rod 16 on its longitudinal axis, the end of the rod being provided with a notch, as shown, for the reception of a suitable tool for turning it. When turned, the threads on head 15 cause the turns of the spring 13 to be moved along the head, the spring being held from turning (and thus coniined to axial movement only) by an end 84 `of the spring which slides in a vertical groove 84b defined by a pair of spaced walls fastened to the inner surface of sleeve 69. On portion 5|k of the contact lever is an upwardly projecting ear 85 to which is connected one end of a tension spring 86, the other end of which. is connected to casing top wall I through the intermediary of a pin 81. Spring 86 serves to hold pin 54 normally in engagement with the hat sur face of lever arm 55, and serves to make contact lever 50 follow .the movements of lever arm 5t, In substance it forms a yielding pivotal connection betweencontact lever 50 and lever arm 55.

Between 1 two ears depending from the underside of lever portion 52` is mounted a roller 88 adapted to be' engaged 4bya cam surface 89 carried by an arm 90 on the shaft of a torque motor 9|. Arm 90 is biased tota position wherein cam surface 88 4is spaced from the roller 88 by a spring";92 which holds a surface of the arm against an adjustable stop screw 93. Stop screw 93 and also an adjustablelscrew 93a for the one end of spring 92 are vcarried by a plate 93b fastened to the frame of the torque motor. The torque motor` 9| is mounted on bottom casingl wall 2 by means of posts 94 and studs 95.

At 06 is indicated an electricalfconnector comprising a number of contact pins carried in an insulating Ablock fixed in side wall 5 of the casing. At 91'are indicated contacts through which electrical conductors may be connected to the limit switches 21 and`28. The winding of the torque motor is indicated at 98. A wiring diagram for the regulator is not shown in the drawings as the specific arrangement of the wiring system in which the regulator is used forms no part of the present invention.

In Fig. 5 is illustrated diagrammatically the regulator or governor connected to the control valve of a, turbosupercharger, so much oi the arrangement being illustrated as is needed for an understanding of my invention. Referring particularly to Fig. 5, the turbosupercharger is shown as comprising a gas turbine |00 to which gases, for example exhaust gases from an aircraft engine, may be conveyed by a conduit |01. The turbine wheel of the gas turbine is indicated at |02 and the waste conduit is indicated at lilS. In waste conduit |03 is a suitable valve |04 on the shaft of which is fixed an operating arm |65. The compressor of the turbosupercharger is indicated at |06, the inlet conduit being indicated at |01 and the discharge conduit at |08. The inlet conduit |01 may have an inlet end which faces into the slip stream of the aircraft, is well understood, and the discharge conduit may connect to the carburetor of the aircraft engine. Preferably, the casingof the regulator or governor has its interior connected to inlet conduit |01 by a pipe line |09 so that the pressure in the casing is the ram pressure, the ram pressure being somewhat higher than ambient pressure. However, the casing may be connected directly to atmosphere so that the pressure in it is ambient pressure, and it is to be understood that by the term ambient pressure as used ner already descr The spring 13'may be set by control rod 84 in the claims, I mean either the 'surrounding atconnected through gearing H4 to acontrol motor H5. Motor H5 may be suitably connected into a control circuit which includes the contact arm 5|, thespring contact strips 38 and 39, and the limit switches. As already pointed out, the specific circuit arrangement forms no part of my present invention and as such circuit arrangements are known, a circuit arrangement lhas not been illustrated in the drawings. For the purposes of the present invention, it is only necessary to note that when contact strip 53 on con-- tact lever 50 engages one or the other of the contact buttons on spring contact arms 38 and 39, motor H5 is operated in one direction or the other to effect opening or closing movement of the valve I 04. And that when valve |04 moves, head is turned to eect turning movement of arm I3 in a direction to'move away from contact strip 53 the control button with which it is in engagement. This latter forms a followother pressure which is a measure of a function to be regulated, which pressure and function .respond to adjustment of the waste valve |04.

l'I'rle pressure conveyed through pipe line 12 to the interior of bellows 61 operates on the bellows in a direction to distend it in opposition to the tension of spring 13. Bellows 61 and 6| are arranged in opposed relation to each other and since beilbws 6| is evacuated Ianci both bellows are subjected on their exteriors to the same pressure, i. e.. the pressure obtaining inside the casing, then variation in pressure in the casing tends to be equalized as to its effect on the bellows system. If the pressure in bellows 61 increases, the bellows is distended effecting. movement of the leverage system to bring contact strip 63 on the end of contact arm 50-into engagement with the contact button or the lower contact strip 36 and this functions to effect 0D- eration of motor H5 to adjust valve |04 in a direction to cause that which is being controlled to restore the pressure vconveyed through pipe line 12 to the interior of bellows 61 to a new value which will again bring the system into equilibriumwithv the` contact strip -5,3 standing midway between'the two contact buttons.A Similarly, if I the pressure 'in bellows 61 decreases,

then spring 13 effects a collapsing movement of the bellows to effect operation of motor H5 in the opposite direction to piove valve |04 to again restore the pressure to a value which will bring the system into,` equilibrium. 'In each instance, the .follow-up mechanism -operates in the manfor a certain pressure which it is desired to hold.

Pipe line 12 connects light load to full load depending upon the altitude of the aircraft for as the aircraft altitude increases, the ambient pressure becomes less and less which means more and more work for the compressor to do since it must compress the air from ambient pressure toa pressure corresponding to that for which the regulator is set. And during this process, it will be clear that the pressure in the regulator casing will decrease as the altitude decreases.

As is known, a follow-up device as described has for its function to provide a certain width of regulation or pressure droop between light load and full load of the device being regulated, in the present instance a turbosupercharger, to give stability to the regulator and prevent hunting. This means-that for any given setting of the regulator the pressure maintained at full load 'is a certain amount lower than at light load.

This difference in pressure between light load and-full required to give stability of operation of the regulator may be objectionable ln certain installations, it being desirable-often to maintain more nearly a constant pressure irrespective of the load. According to one feature of my invention, I provide means for modifying or correcting for the inherent width of regulation of the regulator whereby more nearly constant pressure may be maintained over the entire load range of the regulator or governor. lThis result I accomplish' in carrying out my invention by making either the pressure bellows 61 of less diameter than the evacuated bellows 6I; by providing for bellows 61 a lever arm shorter than that of bellows 6|, or by. a combination of the two means. Preferably, I utilize a combination of the two means; and, as shown in the drawings, bellows 61 is of smaller diameter than bellows 6I and the length of the lever arm for bellows 6I, i. e., the ldistance from its pivot pin 56 to nut 60, may be made greater than the length of the lever arm for bellows '61, i. e., the distance from its pivot point 56 to pivot connection 68.

Assume first that the lever arms for the two bellows are the same length but that the-bellows 61 is smaller. in diameter than the bellows 6|. The torque resulting from the pull of each bellows on lever 5I is proportional to the respective areas of the bellows. Accordingly, as the pressure in the casing decreases with increase in altitude, (which means also increase in load on the turbosupercharger) the effective torque reeach bellows on the lever arm is proportional the respective lengths of the lever arms. Accordv ingly, then here again, as the pressure in the It may be a pressure which is a measure of load on the aircraft engine and which is maintained y by operation of the turbpsupercharger. For the turbosupergharger to maintain such pressure, it

'may be required to operate'at anywhere from casing decreases with increase in altitude (which means also increase in load on the supercharger) the effective-torque resulting from the pull of bellows 6I on the lever arm decreases proportionately more rapidly than doesthe effective torque resulting from the pull of bellows 61 on the lever arm whereby again a proportionately higher pressure in bellows 61 will be required to reestablish a balanced condition of torques.

From the foregoing, it will be seen that the same resultI is obtained either by making bellows 6| larger in diameter than bellows El or by making the lever arm of bellows 6| longer than the lever arm of bellows 61. And either arrangement may be employed alone. Preferably, however, as shown in the drawings, I employ a combination of the two arrangements, making the bellows 6I larger in diameter than the bellows Si by an amount to give the approximate desired modification in or correction for the nor- .ial width of regulation of the regulator and then adjusting the respective lengths of the two lever arms to give the exact desired modification in or correction for the normal width of reguiation of the regulator. As shown in the drawings, the arrangement is such that the length of the lever arm of -bellows 6I may be adjusted to be either greater than, equal to, or less than the length of the lever arm of bellows 61 thus providing for a range of adjustment of the width of regulation to either side of that set by the diierential between the diameters of the two bellows.

In explanation of the functioning of the regulator, assume that the regulator apparatus is in operation -on an aircraft; that at the then altitude of the aircraft, the turbosupercharger is operating at a speed to 'maintain in bellows 61 the control pressure for which the 'regulator is set by control rod 84, and that the parts are in equilibrium with contact strip 53 midway between the contact buttons on contactstrips 38 and 39. Now assume that the aircraft climbs Vto a higher altitude. This means that the turbosupercharger must operate at a higher speed to hold the pressure for which the regulator is set. As the aircraft ascends, the supercharger at its then operating speed is no longer able to maintain the pressure for which the regulator is set. As a the two result, the pressure in bellows 51 decreases and this operates the regulator contacts to effect adjustment of valve IM in a direction to increase the speed of the turbocharger in an effort to restore the pressure to a new value which will bring the regulator parts back into a position of equilibrium. By reason of the follow-up device, the new pressure required to bring the parts back into equilibrium would be a certain amount less than the previous pressure due to the width of regulation or droop of the governor. With increase in altitude, the pressure in the control casing decreases and this change in pressure in the control casingacts on the bellows system in a direction tending -to increase the pressure required in bellows 61 to restore the regulator parts back to a position of equilibrium. Thus, two factors enter into the readjustment of the regulator; first, the follow-up device which tends to permit the regulator to assume a position of equilibrium. at a pressure lower than that previously and, second, the bellows system which in substance acts in opposition to the follow-up mechanism and tends to require a pressure higher than that which would be required by the follow-up system alone in order to restore the regulator parts to equilibrium. Thus. the bellows system acts, so-to-speak, to correct for the width of regulation inherent in the follow-up mechanism. The follow-up mechanism functions first, it functioning along with the movement of the valve Illlll while the bellows system functions afterwards as the pressure changes in the bellows 61 due to 'the change in the speed of the turbosupercharger. Thus, it may be considered that the followup mechanism operates rst to set the control after which the bellows system operates to readjust the pressure so as to correct to a predetermined extent for the inherent width of regulation of the regulator.

It will be understood that the operation is the same when the aircraft decreases altitude except in the opposite sense.

Torque motor 9| functions as an overspeed device for the turbosupercharger, its winding 98 being connected in a suitable circuit associated with the turbosupercharger in a manner such that when the speed of the turbosupercharger exceeds a predetermined high value, cam 89 will be turned in a clockwise direction as viewed in Fig. 5, to bring the cam into engagement with roller 88 whereupon the torque-motor takes control of movement of contact lever 50. Here again, the circuit arrangement utilized forms no part of my present invention and is not needed for a complete understanding of my invention. Accordingly, it has not been illustrated. An arrangement such as that disclosed in the aforementioned Hoffman and Crever application may be utilized.

What vI claim as new and desire to secure by Letters Patent of the United States is:

l. As an article of manufacture, a regulator comprising a casing, a lever mechanism pivotally mounted in the casing, an evacuated bellows having one end iixed and the other end connected to the lever mechanism, a second bellows having one end xed and the other end connected to said lever mechanism in opposed relation to the evacuated bellows, walls defining a passage which connects with the interior of said second bellows and through which it may be subjected to a control pressure, means for adjusting the lengths of the lever arms of said two bellows relatively to each other, said evacuated bellows being larger in diameter than the other bellows and conduit means communicating with the casing and arranged to subject the exterior of both bellows" to a common pressure.

2. A regulator comprising a casing, a rst contact lever pivoted in the casing, a second contact lever pivoted in the casing and having contacts adapted to be engaged by the first contact lever, said second contact lever being adapted to form a part of a follow-upmechanism for the regulator,

a pair of bellows connected to said first contact lever in opposed relation to each other, one of said bellows being evacuated and the other having an opening through which a control pressure may be conducted to its interior, and means whereby the lengths of the lever arms of the bellows may be adjusted relatively to each other.

3. A regulator comprising a casing, a first contact lever pivoted in the casing, a second contact `lever pivoted in the casing and having contacts MARTIN LEvINE. 

